I know that several other have other opinions, but I would start with a packaged bundle that has php,mysql, and apache all wrapped up into one. Try using easyPHP, it can be found at http://www.easyphp.org
Once you get it downloaded (about 10 megs) and getting it up and running, try searching google for php tutorials, there are literally thousands of them out there. Dont let it overwhelm you!! That should get you started!!!🆒